Combined aerobic and resistance training have unique benefits for maintaining a physical activity (PA). However, the optimal training program for combining these two modes of training in older adults is unknown. This study builds on current and past studies showing that training induced gains in aerobic fitness, muscle strength, and ease of PA are important for maintaining an active lifestyle, a favorable body composition, and high bone density. Traditionally 3 d/wk combined training has been felt to be optimal while recent studies suggest 1 d/wk combined training may create similar adaptations as more frequent training. However, our previous and ongoing studies suggest that 1 d/wk combined aerobic and resistance training (C1) may be insufficient stimulus to induce optimal adaptations and that 3 d/wk combined training (C3) may be too frequent a stimulus for older adults. This study will enable us to compare the effects of C1, 2 d/wk combined training (C2), and C3 on fitness, body composition, ease of PA, PA, and total free-living energy expenditure (TEE). We hypothesize that C2 will result in a larger increase in muscle size, bone density, strength, aerobic capacity, power, ease of PA, PA, and TEE than either C1 or C3. Circulating cytokinejs andpsychological mood states linked to chronic overstress will also be examined. Objectives: We will examine changes in circulating cytokines, mood states, muscle size, bone density, aerobic capacity, strength, power, ease of PA, PA, and TEE following 16 and 32 wks training. Design: We will to evaluate 78 (>60 yrs) Black and White women matched for age, race, and BMI into C1, C2, or C3 groups prior to, after 16, and after 32 wks training. Women will undergo evaluation of metabolic parameters in a General Clinical ResearchCenter. Significance: This study should provide insight into the effects combined training frequency has on improving fitness, ease of PA, and maintenance of a high TEE. Such information is critical to our understanding of ways to improve well being, quality of life, and independence of an aging population.